The development of information systems, such as the Internet, and various on-line services for accessing the information systems, has led to the availability of increasing amounts of information. As computers become increasingly powerful and versatile, users are increasingly employing their computers for a broad variety of tasks. Accompanying the increasing use and versatility of computers is an increasing desire on the part of users to increasingly rely on their computing devices to perform their daily activities. For example, anyone with access to a suitable Internet connection may go “on-line” and navigate to the information pages (i.e., the web pages) to gather information that is relevant to the user's current activity.
Many search engine services, such as Google and Yahoo!, provide for searching for information that is accessible via the Internet. These search engine services allow users to search for display pages, such as web pages, that may be of interest to users. After a user submits a search request (i.e., a query) that includes search terms, the search engine service identifies web pages that may be related to those search terms. To quickly identify related web pages, the search engine services may maintain a mapping of keywords to web pages. This mapping may be generated by “crawling” the web (i.e., the World Wide Web) to identify the keywords of each web page. To crawl the web, a search engine service may use a list of root web pages to identify all web pages that are accessible through those root web pages. The keywords of any particular web page can be identified using various well-known information retrieval techniques, such as identifying the words of a headline, the words supplied in the metadata of the web page, the words that are highlighted, and so on. The search engine service may generate a relevance score to indicate how relevant the information of the web page may be to the search request based on the closeness of each match, web page importance or popularity (e.g., Google's PageRank), and so on. The search engine service then displays to the user links to those web pages in an order that is based on a ranking determined by their relevance.
Unfortunately, users of the information systems encounter an information overload problem. For example, the search engine services often provide its user irrelevant search results, thus forcing the user to sift through a long list of web pages in order to find the relevant web pages. Compounding this problem is the constantly changing and expanding volume of information, and the difficulty users encounter in keeping abreast of the constantly changing information to determine the information that is credible and relevant to the user.